Automotive moldings

Perhaps the ultimate low-weight use of foamed POs in vehicles comes in the form of expanded polypropylene (EPP) bead materials, which can be molded into cushioning materials for sound-dampening, seating, storage systems, energy absorption, and occupant protection. A couple of recent uses of EPP are covered in Case 13.2. 

CASE 13.2 EXPANDED PP FOR AUTOMOTIVE WEIGHT SAVINGS AND SAFETY [13-13, 13-14] 

Problem Automakers need more options for reducing veW-cle mass and mcieastng occupant safety 

Objective Lightweight, impaci-resistant, PO-compahhle (and recyclahle) materials. 

EPP bead foams are already heavUy used in vehicles for a variety of applications, given EPP s energy absorption, moldabU-Ity, and extremely low density. Automakers at BMW and Ford have recently adapted the material Into rrmovative uses. 

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Patent Number US 5656675 A 19970812 AUTOMOTIVE MOLDED ROOF MATERIAL AND PROCESS FOR PRODUCING THE SAME Kobayashi T Morita K Suzuki S Mitsui Petrochemical Industries Ltd. 

Propene (propylene) H2C=CHCH, Polypropylene Automotive moldings, rope, carpet fibers... 

Polymer made at an NCO/OH ratio of 1.03 was found to have an optimum rate of hardness build-up. Its hardness build-up curve, shown in Figure 6, was essentially superimposable with that of a commercially acceptable PTMG-based polymer and in field trials it molded at the same cycle time without difficulty. Thus molding behavior in large automotive molds could be related to a simple test which can be carried out on a relatively small sample. 

MAJOR APPLICATIONS Tires and tire products, sealants, belts, gaskets, hoses, automotive molded articles, rubber bands, gloves, footware, sporting goods, and rubber sheeting. Block copwlymers with styrene are used for adhesives and footware. 

Croda Polymer Additives IncroMold additives provide internal filler and glass-fiber lubrication and mold release in one case, 0.45% additive in a 30%-glass-fiber, carbon-black-pigmented PP automotive molding reportedly increased output by 20% and eliminated the need for a silicone spray-on mold release [11-24]. 

Traditionally, material design requirements that suit such demanding end-use applications have been limited within the domain of engineering plastics based on polyamide 6 or 66, polyester alloys, and polyacetal type resins. However, as described in Chapter 1, glass fiber-reinforced polypropylene (GFRP) composites continue to gain a market share in automotive molded parts. 

Tinuvin 123), have been used extensively in automotive molding and coating applications. Higher MW versions have been developed and are targeted for greenhouse film applications (58), but commercial viability of these products is yet to be demonstrated. 

Due to the low paint curing temperatures for thermoplastic automotive molded parts, two component or two pack clearcoats are typically used. All the paint used needs to provide sufficient flexibility to ensure high-impact performance of the molded part even at low temperature (2). If a clearcoat is highly flexible and exhibits a hard surface to easily polish defects caused by coating impurities, it has attributes that empirically appear to contradict one another. However, through today s advanced resin chemistry, products are available that offer both ambient temperature polishing capabibty and excellent flexibility, as measured through low-temperature impact. 

Rubber-modified styrene-acrylonitrile copolymers (ABS) This material has a continuous SAN phase with about 15 wt.% rubber modification, generally polybutadiene. In most applications, impact resistance is the reason for the selection of ABS. Applications include housings and covers for appliances and tools, plus a variety of automotive moldings. 

Recommended for products automotive molded parts, lubricants, tires ... 

Recommended for products automotive belts. automotive molded... 

Recommended for products automotive interiors, automotive molded parts, automotive shoes boots, fuel hose, high temperature applications, seals, telephone wire, wire cable ... 

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